Nearly all of the prior art governing mechanisms now in use employ speed responsive devices utilizing centrifugal force, such as flyballs or similar structural devices, acting directly or indirectly on the speed regulating means of the power unit. Such mechanisms require speed responsive devices of different sizes and spring loading for different size power units, thus making it necessary for suppliers of governing mechanisms to carry a large inventory of many different sizes.
Furthermore, any failure or faulty operation of the conventional speed responsive flyball governor or equivalent device will result a wide open motive supply and a consequent running away operation of the power unit being regulated. This can be disastrous to a Diesel engine driven truck, bus or similar vehicle, which cannot be stopped by the simple expedient of cutting off the ignition switch as in internal combustion engines of the spark ignition type, since in Diesel trucks the fuel cut-off valve is generally located under the hood or in a position where it is not readily accessible to the operator when the vehicle is in motion.